Noninvasive fetal genotyping of human platelet antigen‐1a using targeted massively parallel sequencing

Abstract

We have successfully established massively parallel sequencing as a novel reliable method for noninvasive genotyping of fetal HPA-1a alleles. This technique may also allow the safe detection of other fetal blood group polymorphisms frequently involved in FNAIT and hemolytic disease of the newborn.

Current perspectives on fetal and neonatal alloimmune thrombocytopenia – increasing clinical concerns and new treatment opportunities

“…Assays for noninvasive prenatal testing to detect fetal HPA-1a DNA in maternal plasma have been developed and are in use in many research laboratories, but are not yet implemented in routine clinical practice in most countries 68–72. Determination of paternal zygosity may be relevant.…”

“…The clinical outcome of ICH due to FNAIT is reported to be worse compared to neonatal ICH from other causes75,76 and may be connected to the typical locations of the bleedings in the brain. Severe neurological complications are found in 36%–68% of ICH cases24,26,77,78 and fetal or neonatal death due to ICH is reported in the range of 9%–46%24,57,68,79 when evaluated retrospectively. A large cohort study from the international No Intracranial Hemorrhage (NOICH) registry described 43 cases of ICH caused by FNAIT in depth and found that the majority of bleedings (54%) happened before the third trimester and 67% before 34 gestational weeks 77.…”

Noninvasive prenatal paternity testing using targeted massively parallel sequencing

“…Background signals in the cfDNA sequencing reads were evaluated by the fraction of nonspecific alleles that did not belong to the known bi‐allelic system . As a result, the levels of nonspecific alleles were zero at most loci for the 34 maternal cfDNA samples, and the overall level of the background signals was detected with a mean (± SD) frequency of 1.02% (± 0.24%) with a range from 0.00% to 9.00% (Fig.…”

An SNP panel for the analysis of paternally inherited alleles in maternal plasma using ion Torrent PGM

“…1) at each locus with a minimum coverage of 1000×, as previously described [25,26]. As a result, the levels of non-specific alleles were zero at most A-SNP loci for the 20 maternal cfDNA samples, except for 58 loci with detectable nonspecific alleles (Table S3).…”

“…Then, the overall level of the background signals was detected with a mean (±SD) frequency of 0.0028% (±0.049%), ranging from 0% to 1.6%. It is expected that an a priori defined cutoff value of 2% for paternally inherited foetal alleles was clearly separated from the background signals [26].…”